Glaucoma
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High Yield Notes
13 pages
Flashcards
Glaucoma
of complete
Questions
USMLE® Step 1 style questions USMLE
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Memory Anchors and Partner Content
External References
First Aid
2024
2023
2022
2021
α-agonists
glaucoma treatment p. 567
β -blockers p. 245
glaucoma treatment p. 567
Carbachol p. 239
glaucoma p. 568
Cholinomimetic agents p. 239
glaucoma treatment p. 567
Closed-angle glaucoma p. 551
pilocarpine for p. 239
Diabetes mellitus p. 350-358
glaucoma and p. 551
Diuretics
glaucoma treatment p. 567
Echothiophate
glaucoma p. 568
Eye disorders
glaucoma p. 551
Glaucoma p. 551
acetazolamide for p. 624
atropine p. 240
β -blockers for p. 245
carbachol for p. 239
diabetes mellitus and p. 350
diagnosing p. 239
drugs for p. 567
epinephrine for p. 241
pilocarpine for p. 239
Sturge-Weber syndrome p. 539
Headache p. 532
glaucoma p. 551
Open-angle glaucoma p. 551
carbachol for p. 239
epinephrine for p. 241
pilocarpine for p. 239
Physostigmine
glaucoma p. 568
Pilocarpine p. 239
glaucoma p. 568
Prostaglandins
glaucoma treatment p. 567
Transcript
Content Reviewers
Glaucoma is actually a group of eye diseases that are usually due to intraocular hypertension, or increased pressure in the eye, which damages the optic nerve and if left untreated can lead to blindness.
Taking a closer look at this cross section of the eye, you can see that it’s split up into different chambers: The anterior chamber includes the area from the cornea to the iris, the posterior chamber is this really narrow space between the iris and the lens.
And then this larger vitreous chamber includes the space between the lens and the back of the eye.
Not to be too confusing, but both the anterior and posterior chambers are located in the anterior segment of the eye, while the vitreous chamber is part of the posterior segment of the eye.
Typically all of the chambers in the eye are filled with fluid.
The chambers in the anterior section are filled with a liquid called aqueous humor, and the posterior section is filled with vitreous humor.
The aqueous humor is a transparent, watery fluid that is secreted by the ciliary epithelium, which in addition to secreting aqueous humor and providing nutrients to the lens and cornea, it provides structural support and helps to keep the shape of the eye.
So that fluid’s secreted into the posterior chamber, and then flows through a narrow space between the front of the lens and the back of the iris through the pupil to the anterior chamber.
From there the fluid flows out of the eye through the trabecular meshwork, which is a spongy tissue that acts like a drain, and this allows the fluid to go down into a circular channel called the canal of Schlemm and finally into aqueous veins that are part of the episcleral venous system—the veins around the sclera of the eye.
In glaucoma, part of this aqueous humor drainage pathway becomes partially or completely blocked, so that fluid can’t easily drain out.
This causes the pressure within the fixed space of the anterior chamber to quickly build up causing intraocular hypertension, which is defined as pressure greater than 21 mmHg or 2.8kPa.
Sources
- "Robbins Basic Pathology" Elsevier (2017)
- "Harrison's Principles of Internal Medicine, Twentieth Edition (Vol.1 & Vol.2)" McGraw-Hill Education / Medical (2018)
- "Pathophysiology of Disease: An Introduction to Clinical Medicine 8E" McGraw-Hill Education / Medical (2018)
- "CURRENT Medical Diagnosis and Treatment 2020" McGraw-Hill Education / Medical (2019)
- "Effects of Prostaglandin Analogues on Aqueous Humor Outflow Pathways" Journal of Ocular Pharmacology and Therapeutics (2014)
- "Glaucoma" Primary Care: Clinics in Office Practice (2015)
- "The current research status of normal tension glaucoma" Clinical Interventions in Aging (2014)
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